Both speech recognition and speaker verification application often use an enrollment process to obtain reference speech patterns for later use. Speech recognition systems that use an enrollment process are generally speaker dependent systems. Both speech recognition systems using an enrollment process and speaker verification systems will be referred herein as speech reference systems. The performance of speech reference systems is limited by the quality of the reference patterns obtained in the enrollment process. Prior art enrollment processes ask the user to speak the vocabulary word being enrolled and use the extracted features as the reference pattern for the vocabulary word. These systems suffer from unexpected background noise occurring while the user is uttering the vocabulary word during the enrollment process. This unexpected background noise is then incorporated into the reference pattern. Since the unexpected background noise does not occur every time the user utters the vocabulary word, it degrades the ability of the speech reference system's ability to match the reference pattern with a subsequent utterance.
Thus there exists a need for an enrollment process for speech reference systems that does not incorporate unexpected background noise in the reference patterns.